The Z2S22-30B Type Modular Hydraulic Operated Check Valve is a pilot-operated sandwich plate check valve designed to securely lock hydraulic actuators and prevent unintended movement caused by load pressure or internal leakage. The valve allows free flow in one direction while blocking reverse flow until pilot pressure is applied, ensuring safe and reliable load-holding performance in hydraulic systems.

Designed according to ISO 4401 standards, the Z2S22-30B can be installed directly between directional control valves and subplates, providing a compact and efficient solution for load retention and actuator positioning.

Working Principle

The Z2S22-30B incorporates pilot-operated poppet elements in both working lines.

Free Flow Direction

Hydraulic oil flows freely through:

• A1 → A2
• B1 → B2

The poppet opens automatically when oil flows in the permitted direction.

Reverse Flow Blocking

When hydraulic oil attempts to flow backward:

• The poppet closes tightly against the valve seat.
• Reverse flow is blocked.
• Hydraulic cylinders or actuators remain securely locked.

Pilot Release Function

When pilot pressure is applied from the opposite hydraulic port:

• The pilot piston pushes the poppet open.
• Reverse flow becomes possible.
• The actuator can move smoothly and safely.

This design ensures accurate actuator positioning and prevents unintended load movement.

Product Features

• Pilot-operated hydraulic check valve
• Sandwich plate modular design
• Reliable load-holding function
• Leak-free poppet-type sealing
• Free flow in one direction
• Pilot-controlled opening in reverse direction
• High-pressure and high-flow capability
• Compact installation structure
• Excellent operational stability
• Long service life with low maintenance requirements